The present invention relates to an inflatable apparatus for helping to protect a vehicle occupant in the event of a side impact to a vehicle and/or a vehicle rollover.
It is known to inflate an inflatable vehicle occupant protection device to help protect a vehicle occupant in the event of a vehicle collision. One particular type of inflatable vehicle occupant protection device is an inflatable curtain that inflates from the roof of the vehicle downward inside the passenger compartment between a vehicle occupant and the side structure of the vehicle in the event of a side impact or rollover. A known inflatable curtain is inflated from a deflated condition by inflation fluid directed from an inflator to the inflatable curtain through a fill tube.
The present invention relates to a method for helping to protect an occupant of a vehicle that has a side structure and a roof. The method includes the step of providing an inflatable vehicle occupant protection device that is inflatable away from the vehicle roof into a position between the side structure of the vehicle and a vehicle occupant. The protection device includes overlying panels that are interconnected to define an inflatable volume of the protection device. A thickness of the protection device is determined when the protection device is inflated. The thickness is measured between overlying points on the overlying panels at a location where the head of an occupant may contact the protection device.
A pressure is determined as a predetermined function of the thickness of the protection device and of a velocity at which a head having a given mass may impact the protection device. The pressure has a magnitude sufficient to prevent the head from striking the side structure through the thickness of the protection device when the head impacts the protection device at and below the velocity. An inflation fluid source is provided. The inflation fluid source provides inflation fluid to the inflatable volume to inflate the protection device to at least the determined pressure.
The present invention also relates to a method for determining a pressure to which to inflate an inflatable vehicle occupant protection device inflatable between the side structure of a vehicle and a vehicle occupant. The method includes the step of determining a velocity at or below which it is desired to prevent a head having a given mass from striking the side structure through a thickness of the protection device. A plurality of sample inflated thicknesses are selected. The method also includes the step of determining for each of the sample inflated thicknesses a corresponding required inflation pressure. The required inflation pressure is just sufficient to prevent a head travelling at or below the determined velocity from striking the side structure through an inflatable vehicle occupant protection device having the sample inflated thickness. The method also includes the step of determining an equation that expresses pressure as a function of thickness. The equation is determined such that the equation when solved for each of the sample inflated thicknesses provides a corresponding one of the required inflation pressures. The equation is then used to determine the pressure to which to inflate the protection device as a function of the thickness.
The present invention also relates to a method for determining a pressure to which to inflate an inflatable vehicle occupant protection device inflatable between the side structure of a vehicle and a vehicle occupant. The method includes the step of determining a velocity at or below which it is desired to prevent a head having a given mass from striking the side structure through a thickness of the protection device. A plurality of sample inflated thicknesses are selected. The method also includes the step of determining for each of the sample inflated thicknesses a corresponding required inflation pressure. The required inflation pressure is just sufficient to prevent a head travelling at or below the determined velocity from striking the side structure through an inflatable vehicle occupant protection device having the sample inflated thickness. The method further includes the step of generating a plot that plots each of the sample inflated thicknesses versus its respective required inflation pressure. A curve is then fitted to the plot and the pressure to which to inflate the protection device is determined using the curve.
The present invention also relates to a method for helping to protect an occupant of a vehicle that has a side structure and a roof. The method includes the step of providing an inflatable vehicle occupant protection device that is inflatable away from the vehicle roof into a position between the side structure of the vehicle and a vehicle occupant. The protection device includes overlying panels that are interconnected to define an inflatable volume of the protection device. The method also includes the steps of determining a pressure to which to inflate the protection device and providing an inflation fluid source for providing inflation fluid to the inflatable volume to inflate the protection device to at least that pressure. The method further includes the step of determining the thickness of the protection device as a function of the pressure and of a velocity at which a head having a given mass may impact the protection device. The thickness is measured between overlying points on the overlying panels when the protection device is inflated at a location where a head may contact the protection device. The thickness is sufficient to prevent the head from striking the side structure through the protection device when the protection device is inflated to the pressure and the head impacts the protection device at or below the velocity.
The present invention further relates to a method for determining a thickness for an inflatable vehicle occupant protection device inflatable between the side structure of a vehicle and a vehicle occupant to a given pressure. The method includes the step of determining a velocity at or below which it is desired to prevent a head having a given mass from striking the side structure through the thickness of the protection device. A plurality of sample inflated thicknesses are selected. The method also includes the step of determining for each of the sample inflated thicknesses a corresponding required inflation pressure. The required inflation pressure is just sufficient to prevent a head travelling at or below the determined velocity from striking the side structure through an inflatable vehicle occupant protection device having the sample inflated thickness. The method further includes the step of determining an equation that expresses pressure as a function of thickness. The equation is determined such that the equation when solved for each of the sample inflated thicknesses provides a corresponding one of the required inflation pressures. The equation is then used to determine the thickness to which to inflate the protection device as a function of the given pressure.
The present invention also relates to a method for determining a thickness for an inflatable vehicle occupant protection device inflatable between the side structure of a vehicle and a vehicle occupant to a given pressure. The method includes the step of determining a velocity at or below which it is desired to prevent a head having a given mass from striking the side structure through the thickness of the protection device. A plurality of sample inflated thicknesses are selected. The method also includes the step of determining for each of the sample inflated thicknesses a corresponding required inflation pressure. The required inflation pressure is just sufficient to prevent a head travelling at or below the determined velocity from striking the side structure through an inflatable vehicle occupant protection device having the sample inflated thickness. The method further includes the step of generating a plot that plots each of the sample inflated thicknesses versus its respective required inflation pressure. A curve is fitted to the plot and the thickness for the protection device is determined using the curve.